Effects of aging and idiopathic Parkinson's disease on tactile temporal order judgment.

Nishikawa N, Shimo Y, Wada M, Hattori N, Kitazawa S - PLoS ONE (2015)

Bottom Line:
By contrast, the effect of aging was apparent in both conditions.With their arms uncrossed, the temporal resolution (the interstimulus interval that yielded 84% correct responses) in elderly participants was significantly worse compared with young participants.These results indicate that the basal ganglia and dopaminergic systems do not play essential roles in tactile TOJ involving both hands and that the effect of aging on TOJ is mostly independent of the dopaminergic systems.

Affiliation: Department of Neurology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan.

ABSTRACTIt is generally accepted that the basal ganglia play an important role in interval timing that requires the measurement of temporal durations. By contrast, it remains controversial whether the basal ganglia play an essential role in temporal order judgment (TOJ) of successive stimuli, a behavior that does not necessarily require the measurement of durations in time. To address this issue, we compared the effects of idiopathic Parkinson's disease (PD) on the TOJ of two successive taps delivered to each hand, with the arms uncrossed in one condition and crossed in another. In addition to age-matched elderly participants without PD (non-PD), we examined young healthy participants so that the effect of aging could serve as a control for evaluating the effects of PD. There was no significant difference between PD and non-PD participants in any parameter of TOJ under either arm posture, although reaction time was significantly longer in PD compared with non-PD participants. By contrast, the effect of aging was apparent in both conditions. With their arms uncrossed, the temporal resolution (the interstimulus interval that yielded 84% correct responses) in elderly participants was significantly worse compared with young participants. With their arms crossed, elderly participants made more errors at longer intervals (~1 s) than young participants, although both age groups showed similar judgment reversal at moderately short intervals (~200 ms). These results indicate that the basal ganglia and dopaminergic systems do not play essential roles in tactile TOJ involving both hands and that the effect of aging on TOJ is mostly independent of the dopaminergic systems.

pone.0118331.g003: Comparisons of reaction time.The mean reaction time (ordinate) is plotted against the SOA (abscissa) for the young (A), non-PD (B), and PD participants (C). The colors differentiate between the arms-crossed (red) and -uncrossed (black) conditions.

Mentions:
Reaction time was generally shorter in the young participants (Fig. 3A) than in the elderly participants (Figs. 3B, C). In addition, reaction time was generally longer in the PD patients compared with the non-PD elderly participants (Figs. 3B, C). A three-way mixed model ANOVA (group × posture × SOA; group: between-subject factor; posture and SOA: within-subject factors) revealed that the three main effects, group (young, non-PD, PD; F(2, 54) = 18.8, p < 0.0001), posture (uncrossed, crossed; F(1, 54) = 121, p < 0.05), and SOA (-960, -480, …, 960; F(9, 486) = 51.4, p < 0.0001), and all interactions (group × posture: F(2, 54) = 6.9, p < 0.0022; group × SOA: F(18, 486) = 4.2, p < 0.0001; posture × SOA: F(9, 486) = 5.0, p < 0.0001; group × posture × SOA: F(18, 486) = 2.8, p = 0.0001) were significant. Post-hoc tests for the simple main effect of group showed on average that the mean reaction time was significantly different between any combination of the three groups (young/ PD: p < 0.0001, t(32) = 5.9; non-PD/ PD: p = 0.0022, t(38) = 3.2; young/ non-PD: p = 0.0034, t(40) = 3.1, Ryan’s method; young: 720 ± 20 ms, non-PD: 990 ± 22 ms, PD: 1300 ± 31 ms; mean ± s.e.m.). However, it is worth noting that the three-way interaction qualified the main effect in many ways. For example, the simple, simple main effects of group did not reach a level of significance at longer SOAs (-960, -480, -240, 480, 960 ms) when the arms were uncrossed, but were significant at any SOAs when the arms were crossed. That is, the group difference was more marked when the arms were crossed (Fig. 3, red circles) than when the arms were uncrossed (black squares). Longer reaction time in the PD patients compared with the non-PD participants, ~300 ms greater on average, indicates that the motor disorder due to Parkinsonism was present even with medication.

pone.0118331.g003: Comparisons of reaction time.The mean reaction time (ordinate) is plotted against the SOA (abscissa) for the young (A), non-PD (B), and PD participants (C). The colors differentiate between the arms-crossed (red) and -uncrossed (black) conditions.

Mentions:
Reaction time was generally shorter in the young participants (Fig. 3A) than in the elderly participants (Figs. 3B, C). In addition, reaction time was generally longer in the PD patients compared with the non-PD elderly participants (Figs. 3B, C). A three-way mixed model ANOVA (group × posture × SOA; group: between-subject factor; posture and SOA: within-subject factors) revealed that the three main effects, group (young, non-PD, PD; F(2, 54) = 18.8, p < 0.0001), posture (uncrossed, crossed; F(1, 54) = 121, p < 0.05), and SOA (-960, -480, …, 960; F(9, 486) = 51.4, p < 0.0001), and all interactions (group × posture: F(2, 54) = 6.9, p < 0.0022; group × SOA: F(18, 486) = 4.2, p < 0.0001; posture × SOA: F(9, 486) = 5.0, p < 0.0001; group × posture × SOA: F(18, 486) = 2.8, p = 0.0001) were significant. Post-hoc tests for the simple main effect of group showed on average that the mean reaction time was significantly different between any combination of the three groups (young/ PD: p < 0.0001, t(32) = 5.9; non-PD/ PD: p = 0.0022, t(38) = 3.2; young/ non-PD: p = 0.0034, t(40) = 3.1, Ryan’s method; young: 720 ± 20 ms, non-PD: 990 ± 22 ms, PD: 1300 ± 31 ms; mean ± s.e.m.). However, it is worth noting that the three-way interaction qualified the main effect in many ways. For example, the simple, simple main effects of group did not reach a level of significance at longer SOAs (-960, -480, -240, 480, 960 ms) when the arms were uncrossed, but were significant at any SOAs when the arms were crossed. That is, the group difference was more marked when the arms were crossed (Fig. 3, red circles) than when the arms were uncrossed (black squares). Longer reaction time in the PD patients compared with the non-PD participants, ~300 ms greater on average, indicates that the motor disorder due to Parkinsonism was present even with medication.

Bottom Line:
By contrast, the effect of aging was apparent in both conditions.With their arms uncrossed, the temporal resolution (the interstimulus interval that yielded 84% correct responses) in elderly participants was significantly worse compared with young participants.These results indicate that the basal ganglia and dopaminergic systems do not play essential roles in tactile TOJ involving both hands and that the effect of aging on TOJ is mostly independent of the dopaminergic systems.

Affiliation:
Department of Neurology, Juntendo University School of Medicine, Tokyo, 113-8421, Japan.

ABSTRACTIt is generally accepted that the basal ganglia play an important role in interval timing that requires the measurement of temporal durations. By contrast, it remains controversial whether the basal ganglia play an essential role in temporal order judgment (TOJ) of successive stimuli, a behavior that does not necessarily require the measurement of durations in time. To address this issue, we compared the effects of idiopathic Parkinson's disease (PD) on the TOJ of two successive taps delivered to each hand, with the arms uncrossed in one condition and crossed in another. In addition to age-matched elderly participants without PD (non-PD), we examined young healthy participants so that the effect of aging could serve as a control for evaluating the effects of PD. There was no significant difference between PD and non-PD participants in any parameter of TOJ under either arm posture, although reaction time was significantly longer in PD compared with non-PD participants. By contrast, the effect of aging was apparent in both conditions. With their arms uncrossed, the temporal resolution (the interstimulus interval that yielded 84% correct responses) in elderly participants was significantly worse compared with young participants. With their arms crossed, elderly participants made more errors at longer intervals (~1 s) than young participants, although both age groups showed similar judgment reversal at moderately short intervals (~200 ms). These results indicate that the basal ganglia and dopaminergic systems do not play essential roles in tactile TOJ involving both hands and that the effect of aging on TOJ is mostly independent of the dopaminergic systems.